U.S. patent application number 11/974517 was filed with the patent office on 2009-01-29 for lamp.
This patent application is currently assigned to ERCO Leuchten GmbH. Invention is credited to Matthias Bremerich, Leonhard Klose.
Application Number | 20090027892 11/974517 |
Document ID | / |
Family ID | 40121833 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090027892 |
Kind Code |
A1 |
Bremerich; Matthias ; et
al. |
January 29, 2009 |
Lamp
Abstract
The invention relates to and discloses a light fixture (10) for
illuminating a building surface (15), comprising a dished housing
(11) having a light-output opening (24), a light source (12) being
provided on the interior (31) of the housing, indirect light (30a,
30b, 30c) starting from the light source passing through a
light-output opening only after being reflected on reflector
surfaces (21, 22) and direct light (29a, 29b, 29c) starting from
the light source passing through without reflection on reflector
surfaces, a spread lens (23) being provided that is at the
light-output opening and that ensures that the light is spread in
order to illuminate the building surface more uniformly, the
reflector surfaces each comprising a wall region (22) having a
parabolic cross-section and a wall region (21) having an elliptical
cross-section.
Inventors: |
Bremerich; Matthias;
(Lennestadt, DE) ; Klose; Leonhard; (Ludenscheid,
DE) |
Correspondence
Address: |
K.F. ROSS P.C.
5683 RIVERDALE AVENUE, SUITE 203 BOX 900
BRONX
NY
10471-0900
US
|
Assignee: |
ERCO Leuchten GmbH
|
Family ID: |
40121833 |
Appl. No.: |
11/974517 |
Filed: |
October 12, 2007 |
Current U.S.
Class: |
362/297 ; 29/557;
362/308 |
Current CPC
Class: |
F21S 8/022 20130101;
Y10T 29/49995 20150115; F21V 11/00 20130101; F21V 13/04 20130101;
F21W 2131/107 20130101; F21V 7/09 20130101; F21V 5/02 20130101 |
Class at
Publication: |
362/297 ;
362/308; 29/557 |
International
Class: |
F21V 7/09 20060101
F21V007/09; F21V 7/18 20060101 F21V007/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2007 |
DE |
202007010500.2 |
Jul 26, 2007 |
DE |
202007010501.1 |
Sep 19, 2007 |
DE |
102007044963.3 |
Claims
1. A light fixture for illuminating a building surface, comprising
a dished housing having a light-output opening, a light source
being provided on the interior of the housing, indirect light
starting from the light source passing through the light-output
opening only after being reflected on reflector surfaces and direct
light starting from the light source passing through without
reflection on reflector surfaces, a spread lens being provided that
is at the light-output opening and that ensures that the light is
spread in order to make illumination of the building surface more
even, the reflector surfaces each comprising a wall region with a
parabolic cross-section and a wall region with an elliptical
cross-section.
2. The light fixture according to claim 1 wherein the housing has a
trough shape.
3. The light fixture according to claim 2 wherein the light source
is axially elongated.
4. The light fixture according to claim 2 wherein the spread lens
ensures a spreading of the light in the axial direction.
5. The light fixture according to claim 2 wherein the housing
and/or the wall regions are cylindrical.
6. The light fixture according to claim 2 wherein the spread lens
comprises a plurality of ribs extending transversely to the axial
dimension to form cylindrical lenses.
7. The A light fixture according to any claim 1 wherein a metal
halide lamp, particularly an HID lamp, or a low-voltage halogen
incandescent lamp, is provided as the light source.
8. The A light fixture according to any claim 1 wherein the wall
regions are made of metal, particularly of aluminum, and in
particular are highly reflective.
9. The light fixture according to any claim 1 wherein the light
fixture is a wallwasher.
10. The light fixture according to any claim 1 wherein the light
fixture is an in-ground light fixture.
11. The light fixture according to any claim 1 wherein the light
source is provided at the focal point or close to the focal point
of the elliptical wall region and in the focal point or close to
the focal point of the parabolic wall region.
12. The light fixture according to any claim 1 wherein the light
fixture uniformly illuminates the building surface.
13. The light fixture according to any claim 1 wherein the
elliptical wall region extends approximately across a 205.degree.
angle region around the light source.
14. The light fixture according to any claim 1 wherein the
parabolic wall region extends approximately across a 45.degree.
angle region around the light source.
15. The light fixture according to any claim 1 wherein the
parabolic wall region is mounted relative to the light source such
that the light reflected thereon primarily illuminate a region of
the building surface that is remote from the light fixture and/or
that the elliptical wall region is mounted relative to the light
source such that the light reflected thereon primarily illuminate a
region of the building surface that is close to the light
fixture.
16. The light fixture according to any claim 1 wherein the spread
lens is oriented substantially transversely to a main radiation
direction of the light fixture and particularly at an angle to the
wall to be illuminated.
17. The light fixture according to any claim 1 wherein the light
fixture comprises a dark-light reflector section in the light
radiation direction behind the spread lens.
18. The light fixture according to any claim 1 wherein the
elliptical wall region and the parabolic wall region are connected
by means of a particularly planar intermediate element.
19. The light fixture according to any claim 1 wherein in the light
radiation direction of the light source a masking element is
provided in front of the parabolic wall region.
20. A light fixture for illuminating building surfaces, comprising
a substantially dished reflector element extending along a center
longitudinal axis from an apex region to a light-output opening, at
least one lamp being provided in the interior of the element,
indirect light starting from the light source only passing through
the light-output opening after having been reflected on the inner
surface of the reflector element and direct light starting from the
light source pass through without reflection on the inner surface
of the reflector element, a spread lens being provided that is in
the region of the light-output opening and that ensures spreading
of the light to help produce a more uniform illumination of the
building surface, a plurality of segments comprising surfaces
arcuate inwardly being provided on the inner surface of the
reflector element.
21. The light fixture according to claim 20 wherein the reflector
element is made of metal.
22. The light fixture according to claim 21 wherein the reflector
element is made of press-formed aluminum.
23. The light fixture according to claim 20 wherein the reflector
element comprises a housing that is rotation symmetrical about the
center longitudinal axis with respect to its basic shape, the
housing being cut off or severed at the light-output opening along
a plane at an angle to the center longitudinal axis or comprising
an edge surrounding the light-output opening, the edge extending
along a plane oriented at an angle to the center longitudinal axis
of the reflector element.
24. The light fixture according to claim 23 wherein the spread lens
lies on the plane or cut plane relative to the reflector
element.
25. The light fixture according to claim 20 wherein at least some
segments are each formed by a section of a cylinder, particularly a
circular cylindrical body.
26. The light fixture according to claim 20 wherein all segments
are each formed by a section of a cylinder, particularly a circular
cylindrical body.
27. The light fixture according to claim 25 wherein the center line
of the cylinder is oriented substantially parallel to the center
longitudinal axis of the reflector element or angled to the same at
an angle of less than 45.degree..
28. The light fixture according to claim 25 wherein the inclination
of the center lines of the cylinders, particularly the inclination
thereof relative to a tangent that can be placed on the outer
surface of the reflector element, varies as a function of spacing
of the cylinder from the apex of the reflector.
29. The light fixture according to claim 28 wherein the variation
of the inclination of the cylinder axes of at least several
segments of an angularly extending region is selected such that the
light beams emitted by the light source and impinging upon these
cylindrical segments intersect in a focal point.
30. The light fixture according to claim 29 wherein the focal point
is located outside of the light-output opening of the reflector
element.
31. The light fixture according to claim 30 wherein the focal point
is located close to or in the light-output opening of the light
fixture.
32. The light fixture according to claim 25 wherein the cylinder
axes of a plurality of cylinders having the same distance to the
apex region of the reflector element have the same inclination to
the center longitudinal axis of the reflector element.
33. The light fixture according to any claim 20 wherein the inner
surface of the reflector element is provided with segments along
the entire circumference.
34. The light fixture according to claim 33 wherein the inner
surface of the reflector element is divided into at least two
partial regions.
35. The light fixture according to claim 34 wherein in the
different partial regions differently arcuate and/or differently
sized segments are provided or a varying areal density of segments
exists.
36. The light fixture according to claim 20 wherein the segments
are oriented in rows extending in circles about the center
longitudinal axis of the reflector element and along columns
extending transversely thereto.
37. The light fixture according to claim 34 wherein the different
partial regions are associated with different row numbers.
38. The light fixture according to claim 34 wherein the cylindrical
elements within a partial region are identical in size.
39. The light fixture according to claim 34 wherein the reflector
element comprises two partial regions that each take up an
angularly extending region of approximately 180.degree..
40. The light fixture according to claim 34 wherein in the second
partial region segments are provided that primarily or at least
partly imitate a reflection behavior of a reflector having a
parabolic cross-section.
41. The light fixture according to claim 40 wherein in the first
partial region segments are provided that primarily or at least
partly imitate a reflection behavior of a reflector having an
elliptical cross-section.
42. The light fixture according to claim 34 wherein the first
partial region and the second partial region are separated by a
boundary plane.
43. The light fixture according to claim 23 wherein the boundary
plane and the cut plane intersect along a straight line that
extends perpendicular to the center longitudinal axis.
44. The light fixture according to claim 20 wherein, when viewing a
largest cross-sectional area of the reflector element, a plurality
of segments of a first type are provided on the first side of the
center longitudinal axis of the reflector element and a plurality
of segments of a second type are provided on the other side of the
center longitudinal axis.
45. The light fixture according to claim 20 wherein, when viewing a
cross-sectional area that is oriented perpendicular to the largest
cross-sectional area, a symmetrical shape of the reflector element
relative to the center longitudinal axis is apparent.
46. The light fixture according to claim 44 wherein the segments of
a first type primarily imitate a reflection behavior of a reflector
having an elliptical cross-section.
47. The light fixture according to claim 20 wherein the segments of
a second type primarily imitate a reflection behavior of a
reflector having a parabolic cross-section.
48. The light fixture according to claim 20 wherein the light
source is a substantially punctiform source.
49. The light fixture according to claim 48 wherein a metal halide
lamp, particularly an HID lamp, or a low-voltage halogen
incandescent lamp, or at least an LED, is provided as the light
source.
50. The light fixture according to claim 20 wherein the spread lens
ensures a spreading of the light in a direction transversely to the
largest cross-sectional area.
51. The light fixture according to claim 20 wherein the spread lens
comprises a plurality of ribs to form cylindrical lenses, the ribs
extending along a direction parallel to the largest cross-sectional
area.
52. The light fixture according to claim 50 wherein the light
fixture is a wallwasher.
53. The light fixture according to claim 20 wherein the light
fixture is a recessed light fixture or as a spotlight to be mounted
on the ceiling.
54. The light fixture according to claim 20 wherein the light
fixture uniformly illuminates the building surface.
55. The light fixture according to claim 20 wherein the light
source is located in the focal point or close to the focal point of
a parabolic housing of the reflector element.
56. The light fixture according to claim 20 wherein a partial
region of the reflector for imitating a light distribution of a
parabolic reflector is oriented relative to the light source such
that the light reflected thereon primarily illuminate a region of
the building surface that is remote from the light fixture and/or
that a partial region of the reflector for imitating a light
distribution of a reflector having an elliptical cross-section is
oriented relative to the light source such that the light reflected
thereon primarily illuminate a region of the building surface that
is close to the light fixture.
57. The light fixture according to claim 20 wherein the spread lens
is oriented substantially transversely to a main radiation
direction of the light fixture and at an angle to the wall to be
illuminated.
58. The light fixture according to any claim 20 wherein the light
fixture comprises a dark-light reflector section in the light
radiation direction behind the spread lens.
59. A method for producing a reflector element from a starting
material workpiece, particularly aluminum, comprising a plurality
of segments on the inner surface, characterized by the following
steps: a) providing a starting material workpiece, particularly a
circular aluminum blank, b) applying a relative force between the
workpiece and a male mold, the male mold having an outer shape that
is impressed into the inner shape of the workpiece, c) performing
an axial displacement of the male mold relative to the workpiece to
remove the male mold from the reflector element, d) severing a
section of the reflector element along a separation plane that is
angled relative to a center longitudinal axis of the reflector
element.
60. A light fixture for illuminating building surfaces, the fixture
comprising a substantially dished first reflector element and
flaring along a center longitudinal axis from an apex region toward
a light-output opening, at least one lamp provided in an interior
of the element, a spread lens provided in the region of the
light-output opening to ensure spreading of the light to help
produce a more uniform illumination of the building surface, the
first reflector element being provided with a plurality of segments
having an inwardly arcuate surface, the segments being provided on
the inner surface, the reflector element comprising a housing
rotational symmetrical about the central longitudinal axis with
respect to the basic shape, the housing being cut off or severed at
the light-output opening thereof along a plane at an angle to the
center longitudinal axis, or comprising an edge surrounding the
light-output opening, the edge extending along a plane that is
oriented an acute angle to the center longitudinal axis of the
reflector element, the first reflector element being replaced with
a second reflector element having the same outer dimensions, the
second reflector element therein comprising a plurality of segments
having an inwardly arcuate surface, the types of the segments or
the shape of the segments or the curvatures of the segments being
selected differently in order to achieve a light radiation
characteristic that differs from that of the first reflector
element.
Description
[0001] The invention relates to a light fixture for illuminating a
building surface.
[0002] In particular, the invention relates to a light fixture for
illuminating a building surface, the light fixture evenly
illuminating a building surface with the aid of a spread lens.
[0003] The invention is based on a light fixture previously
publicly used by the applicant and referred to as a lens
wallwasher. Such a light fixture is mentioned, for example, on
pages 342, 343, and 761 of the catalog "ERCO Product Range,
Lighting Controls, Indoor Lighting, Outdoor Lighting, 2006/2007
Issue". The previously known light fixture comprises a reflector
with a parabolic cross-section, the reflector being substantially
rotation symmetrical about the longitudinal center axis
thereof.
[0004] Starting from the light fixture according to the applicant's
prior art that became known through its prior public use, it is the
object of the invention to further develop the known light fixture
such that improved illumination of a building surface is
possible.
[0005] The invention achieves this object with the characteristics
of claim 1.
[0006] The inventive light fixture for illuminating a building
surface comprises, according to the invention, a dished housing
having a light-output opening, a light source being provided in the
interior of the housing, indirect light emanating from the light
source and passing through the light-output opening only after
being reflected on reflector surfaces and direct light starting
from the light source passing through the opening without
reflection on surfaces of the reflector, a spread lens being
provided that is adjacent the light-output opening and that ensures
that the light is spread in order to make illumination of the
building surface more even, the reflector surfaces each comprising
a wall region with a parabolic cross-section and a wall region with
an elliptic cross-section.
[0007] A building surface as defined by the invention is any
surface formed by a building wall, for example a building ceiling,
a floor or a side wall, and a partial building surface. Within the
meaning of the present patent application, a light fixture for
illuminating a building surface can be any indoor or outdoor light
fixture. The light fixture according to the invention is preferably
a wallwasher. The inventive light fixture can also be used to
illuminate objects, such as artwork or merchandise.
[0008] The light fixture according to the invention comprises a
dished housing. A dished housing is any housing having a
substantially arcuate basic shape that is open toward a
light-output opening and that elsewhere is substantially closed.
This may be a housing that is substantially symmetrically about an
axis of rotation. In a preferred embodiment of the invention, the
housing is axially elongated, substantially cylindrical,
particularly trough-shaped.
[0009] A light source is provided in the interior of the housing.
Light is emitted by the light source, the light exiting the housing
through a light-output opening of the housing. The light-output
opening of the housing corresponds, for example, to the
light-output opening of the light fixture or is located adjacent
thereto. In particular, it may be provided directly adjacent the
light-output opening of the light fixture.
[0010] The light source is mounted such that both indirect light
and direct light can pass through the light-output opening of the
housing. Direct light within the meaning of the present patent
application is such light that starting from the light source can
pass directly through the light-output opening of the housing,
without being previously reflected on reflector surfaces. Indirect
light of the light source is that light that has been reflected at
least once on reflector surfaces before passing through the
light-output opening.
[0011] A spread lens is mounted between the light source and the
light-output opening. A spread lens is understood as any
substantially two-dimensional, preferably planar, under certain
circumstances also arcuate, body that can ensure spreading of the
light. The spread lens spreads both the direct light and the
indirect light. Spreading helps produce more uniform illumination
of the building surface. In this way, homogeneous distribution of
the luminous intensity on the building surface to be illuminated
can be achieved.
[0012] The spread lens is formed, for example, by a glass plate
that is smooth on one of its two faces and comprises cylindrical
lenses on the other face. If a light beam impinges upon a
cylindrical lens, the beam is spread into a long line as a function
of the selected focal length of the cylindrical lens. This line
extends at a right angle to the axial direction of the cylindrical
lenses.
[0013] Similarly, all the light emitted by the light source and
impinging upon the spread lens in the form of direct light or
indirect light can be considerably spread.
[0014] With respect to dimensions, the spread lens is selected such
that it covers the entire cross section of the light-output
opening. Viewed in the light emission direction, the spread lens
may be provided in front of or behind the light-output opening of
the housing or at the light-output opening of the housing.
[0015] On the inventive light fixture, the reflector surface is
formed at least by two differently arcuate wall regions. A first
wall region has a parabolic cross-section and a second wall region
has an elliptical cross-section. This shape of the reflector
surfaces makes it possible to provide the light source directly at
the focal points or close to the focal points of both the parabolic
wall region and the wall region with the elliptical cross-section.
This enables a luminous intensity distribution on the wall to be
illuminated, the parabolic shape and the elliptical shape of the
corresponding wall region cross-section being selected
arbitrarily.
[0016] For example, with the inventive light fixture a particularly
even light-intensity distribution across the entire vertical height
or only along part of the height of the building wall to be
illuminated can be achieved. Alternatively, by appropriately
orienting the building light fixture relative to the building
surface to be illuminated, a particularly homogeneous illumination
in a horizontal direction parallel to a floor surface can also be
achieved. Finally, a desired light-intensity distribution can also
be generated in any arbitrary spatial direction.
[0017] The inventive arrangement and combination of wall regions
having parabolic and elliptical cross-sections with one another
enable in particular also an asymmetrical light-intensity
distribution. Particularly when providing the building light
fixture relatively close to the wall, the illumination of regions
of the building surface to be illuminated that are remote from the
light fixture can be achieved. As a result, light-intensity
distributions and particularly uniform, homogeneous illuminations
of building surfaces can be achieved, which were not possible with
the light fixtures according to the prior art.
[0018] According to an advantageous embodiment of the invention,
the housing is trough-shaped. This enables the use of fluorescent
tube lamps, where also a plurality of lamps may be accommodated
longitudinally behind one another in a common housing. It is also
possible to provide a plurality of base bodies longitudinally next
to one another or to provide a plurality of light fixtures
longitudinally in a row. In this way, particularly uniform
illumination of a building surface across a nearly arbitrary
longitudinal extension can be achieved.
[0019] Even when providing only a single light fixture having a
trough-shaped housing, light-intensity distribution that extends in
the longitudinal direction can be achieved on the building surface
to be illuminated. Finally, the trough-shaped housing enables a
simplified design.
[0020] According to a further advantageous embodiment of the
invention, the light source is axially elongated. This enables the
use of conventional, bright lamps from the prior art.
[0021] According to a further advantageous embodiment of the
invention, the spread lens ensures the spreading of the light in
the axial direction. This, in conjunction with a trough-shaped
housing, enables particularly uniform illumination of the building
surface across a building surface that extends longitudinally.
[0022] According to a further advantageous embodiment of the
invention, the housing and/or the wall regions are cylindrical. A
cylindrical shape within the meaning of the present patent
application shall mean that the housing and/or the wall regions
have a constant cross-section along the axial dimension of the
housing. This enables a simplified design since in particular
elongated profiles can be used as components for the design of the
light fixture.
[0023] In this context, it is noted that the reflector surfaces can
be formed directly by wall regions of the housing. The reflector
surfaces, however, may also be provided inside the housing. In the
latter variant, the housing can also be formed directly by a
housing of the light fixture.
[0024] According to a further advantageous embodiment of the
invention, the spread lens comprises a plurality of ribs extending
transversely to the axial extension to form cylindrical lenses. In
this embodiment of the invention, the cylindrical lenses are
preferably perpendicular to the axial extension of the housing.
While the wall regions, particularly the parabolic wall region and
the elliptical wall region, extend along the axial direction and
thus ensure the desired light-intensity distribution, particularly
an extremely homogeneous illumination of the building surface, in a
direction transversely to the axial direction, the light-intensity
distribution can be spread in the axial direction by arraying the
cylindrical lenses transversely to the axial direction. This
enables a uniform illumination of the building surface across a
very large area.
[0025] According to a further advantageous embodiment of the
invention, a metal halide lamp, particularly an HID lamp or a
low-voltage halogen incandescent lamp, is provided. The use of such
bright light sources enables particularly high luminous intensity
levels to be achieved on the building surface to be illuminated. In
this way, even quite large building surface regions, which under
certain circumstances may even be located relatively far from the
light fixture, can be satisfactorily illuminated using a single
light fixture.
[0026] The light source is preferably a fluorescent tube light
source that radiates in a 360.degree. range about the center
longitudinal axis thereof.
[0027] According to a further advantageous embodiment of the
invention, the wall regions are made of metal, particularly of
aluminum. This enables the use of lamps generating a great deal of
heat, such as metal halide lamps or low-voltage halogen
incandescent lamps. In addition, the design of a light fixture
according to the invention can be simplified in this way.
[0028] According to a further embodiment of the invention, the
light fixture is a wallwasher. In this way, an inventive light
fixture can be provided relatively close to the building wall to be
illuminated and a homogeneous illumination of the desired region of
the building wall becomes possible.
[0029] According to a further embodiment of the invention, the
light fixture is an in-ground light fixture. When using the special
parabolic and elliptical wall regions, the light fixture according
to the invention can homogeneously illuminate building surface
regions that are remote from the light fixture and close to the
light fixture.
[0030] According to a further advantageous embodiment of the
invention, the light source is provided at the focal point or close
to the focal point of the elliptical wall region and in the focal
point or close to the focal point of the parabolic wall region. In
this way, the light-intensity distribution on the building surface
to be illuminated can be predicted with relative ease,
conventional, known lighting technology principles being usable. In
particular, it can be taken into consideration that the light
source provided at the focal point of the elliptical wall region
emits indirect light, these indirect light being bundled in a
second focal point. With an appropriate geometric shape of the
elliptical wall region and light-output opening of the light
fixture, optionally also by using a glass cover plate, the light
source is designed such that the second focal point is located
outside the housing, in other words, in the light radiation
direction behind the spread lens and/or adjacent of the
light-output opening of the light fixture, preferably near a cover
glass.
[0031] If the light source is provided in the focal point or close
to the focal point of the parabolic wall region, the indirect
light, which was emitted by the light source and reflected on the
parabolic wall region, leaves the housing along a parallel main
radiation direction. The parabolic wall region is oriented relative
to the light source such that preferably a region of the building
surface to be illuminated that is remote from the light fixture is
illuminated with this indirect light. The wall region having an
elliptical cross-section is provided such that the indirect light
reflected by this wall region preferably illuminates a region of
the building surface to be illuminated that is located close to the
light fixture.
[0032] According to a further advantageous embodiment of the
invention, the light fixture uniformly illuminates the building
surface. In this way, the desired illumination effect can be
achieved in a particularly advantageous manner.
[0033] According to a further advantageous embodiment of the
invention, the elliptical wall region extends along an angle of
between 90.degree. and 270.degree. around the light source. The
elliptical wall region preferably extends along an angle of
approximately 205.degree. around the light source. As a result, the
elliptical wall region covers a larger angle than the angle along
which the parabolic wall region extends.
[0034] Relative to the basic shape of the reflector with the two
wall regions and the light-output opening of the housing, the light
source can be oriented such that, for example, an aperture angle of
approximately 70.degree. relative to the focal point or the
location of the light source is obtained, so that the elliptical
wall region and the parabolic wall region together cover an angle
of approximately 270.degree..
[0035] According to a further advantageous embodiment of the
invention, the parabolic wall region extends substantially along an
angle of between 20.degree. and 100.degree., preferably along an
angle of between 30.degree. and 90.degree., more advantageously
along an angle of approximately 70.degree..
[0036] According to a further advantageous embodiment of the
invention, the spread lens is oriented substantially transversely
to a main illumination direction of the light fixture. In
particular, the spread lens is oriented at an angle to the wall to
be illuminated.
[0037] The light fixture furthermore advantageously comprises a
cover glass, particularly when it is an in-ground light fixture.
The spread lens can then be provided at an angle to the cover
glass, particularly at an angle between 20.degree. and 60.degree.,
further preferred at an angle of approximately 45.degree..
[0038] The elliptical wall region and the parabolic wall region may
be connected to an intermediate element, which may be flat, for
example in order to directly attach the two wall regions to one
another and to compensate for variances in their radial distances
relative to the light source.
[0039] The invention furthermore relates to a light fixture for
illuminating building surfaces according to claim 20.
[0040] The invention is again based on the light fixture described
at the beginning, which is known by the prior public use by the
applicant.
[0041] Also this invention is based on the object of further
developing the light fixture according to the applicant's prior
art, which became known by prior public use, such that improved
illumination of a building surface becomes possible.
[0042] The invention achieves this object with the characteristics
of claim 20.
[0043] The light fixture according to the invention serves to
illuminate building surfaces, particularly for the especially
uniform and homogeneous illumination of large portions of building
surfaces. Within the meaning of the formulation of claim 20
regarding the building surface, the formulation provided above can
be used.
[0044] The light fixture comprises a reflector element that is
substantially dished. It is an arcuate, hollow reflector element
that is substantially shaped like a cup. It has in its interior a
reflector surface. The reflector element is preferably made of
metal, with press-formed aluminum being more preferred.
[0045] The reflector element extends along a center longitudinal
axis from an apex region to a light-output opening. The element
widens along the center longitudinal axis, in other words, the
diameter of the reflector element increases as spacing from the
apex region increases.
[0046] The reflector element preferably has a substantially
parabolic cross-section. Furthermore, the reflector element is
preferably cut along a plane that is oriented at an angle to the
center longitudinal axis of the reflector element.
[0047] The apex region is the region of the reflector element most
widely spaced from the light-output opening. In the apex region of
the reflector element preferably an aperture or opening for a lamp
is provided. Furthermore, the reflector element is preferably
attached to a housing of the lamp near the apex and/or near the
free edge region.
[0048] In the interior of the reflector element at least one lamp
can be provided. Conventional lamps, particularly metal halide
lamps, such as HID lamps, can be used as the lamp.
[0049] The light source is preferably a punctiform light
source.
[0050] The light-output opening of the reflector element is the
opening through which light must pass in order to reach the
building surface to be illuminated. While in the case of a
completely rotation-symmetrical reflector element the light-output
opening has a circular shape, the light-output opening of the
reflector element in the inventive light fixture is surrounded by
an oval edge due to a cut plane that is angled obliquely to the
center longitudinal axis of the reflector element.
[0051] Both direct and indirect light can pass through the
light-output opening. Indirect light refers to all the light rays
that, starting from the light source, only pass through the
light-output opening after being reflected inside the reflector.
Direct light is all the light rays that can pass through the
light-output opening without being reflected in the interior of the
reflector. The building surface to be illuminated is therefore
preferably illuminated by direct and indirect light.
[0052] When using a lamp, that is a light-emitting means that in
the main radiation direction of the lamp, namely in a direction
along the center longitudinal axis of the reflector element,
carries an opaque cap element, it is possible under certain
circumstances that no direct light pass through the light-output
opening. When using lighting means that can radiate also in the
direction of the center longitudinal axis of the reflector element,
advantageously also direct light impinges upon the spread lens.
[0053] A spread lens is provided near of the light-output opening,
preferably directly in the light-output opening of the reflector
element. In accordance with the above explanations provided for
claim 1 and the claims referring back to it, a spread lens is a
two-dimensional, particularly flat element that is designed to be
translucent and comprises a plurality of preferably cylindrical
lenses. The spread lens serves to spread light along a single
preferred direction. The spreading of the light helps produce a
more uniform illumination of the building surface. In the simplest
case, a plurality of rib-shaped elongated cylindrical lenses are
provided on at least one face of the spread lens, which is made for
example of glass.
[0054] A spread lens as defined by the present patent application
can be made of clear or slightly matte-finished glass, for example
sheet glass. The cylindrical lenses can be provided on one or both
faces of the spread lens. Cylindrical lenses can be formed by
convex curvatures or curved surfaces with a concave cross-section.
The cylindrical lenses are preferably continuous and extend from
one edge of the lens plate to the opposite edge of the spread lens,
the cylindrical lenses being formed by a plurality of microlenses
that likewise ensure spreading of the light.
[0055] Inside the reflector element a plurality of segments are
provided, the segments each comprising a surface arcuate toward the
interior of the reflector element. By providing a plurality of
individual segments, it is possible to arbitrarily design the light
radiation characteristics of the reflector element and in this way
achieve any desired illumination characteristic. Particularly when
using cylindrical segments it is possible to adjust the light
distribution along a first direction in the desired manner. By
using a spread lens, additional spreading and uniformity can be
achieved along a second direction perpendicular to the first
direction.
[0056] The invention recognizes that, in order to achieve uniform
illumination of a building surface, a reflector element can be
shaped to achieve a certain lighting characteristic along a first
direction, regardless of the subsequent design and positioning of a
spread lens. By optimizing the inner surface of the reflector
element, that is the active reflection surface, the light radiation
characteristic along the first direction can be influenced in the
desired manner.
[0057] For example, when configuring the inventive light fixture
according to claim 20 as a recessed light fixture or as a spotlight
provided at the building ceiling, it may be desirable to uniformly
illuminate a vertical wall. In order to also evenly illuminate
particularly low regions, that is regions of the vertical wall
close to the floor, or even emphasize these regions, a different
radiation characteristic of the light fixture may be desired than
when particularly high regions, that is regions of the vertical
building surface close to the building ceiling, are supposed to be
illuminated. Both applications can be achieved by appropriately
configuring the segments. It is also possible to illuminate very
high, vertical building walls or surfaces across large areas close
to the light fixture with the inventive light fixture.
[0058] Due to the provision of a plurality of segments, the inner
surface of the reflector element can be designed in many ways. For
example, a first angularly extending region or partial region of
the reflector element can imitate the light radiation
characteristics of a reflector having a parabolic cross-section,
and a different angular portion or another partial region of the
interior of the reflector element can imitate the light radiation
characteristic of a different reflector, for example a reflector
having an elliptical cross-section. In this way, the building
surface can be illuminated in an optimized, particularly
homogeneous manner.
[0059] The inventive combination of a spread lens with a reflector
comprising segments furthermore allows particularly dense luminance
to be achieved outside the spread lens or near the light-output
opening of the light fixture. This reduces undesirable glare
effects for the observer.
[0060] According to an advantageous embodiment of the invention,
the reflector element is made of metal. This enables the use of
lamps radiating high heat energy and a simple design.
[0061] According to a further advantageous embodiment of the
invention, the reflector element is made of press-formed aluminum.
As a result, conventional manufacturing methods and materials can
be employed.
[0062] According to a further advantageous embodiment of the
invention, the reflector element comprises a housing that is
rotation-symmetrical about the center longitudinal axis thereof
with respect to the basic shape, the housing being truncated, sawed
off or cut in another manner at the light-output opening along a
plane at an angle to the center longitudinal axis. It is known from
the prior art to produce reflector elements having a substantially
rotation-symmetrical shape by deforming circular aluminum blanks in
a press. In this respect, reference is made by way of example to
the post-published German patent applications DE 10 2007 035 396
and DE 10 2007 035 528, which are both by the applicant, and the
content of which is hereby included by reference in the present
patent application, also for the purpose of referring to individual
or several characteristics.
[0063] By producing a reflector element having a
rotation-symmetrical housing, the manufacture of the reflector
element can be kept relatively simple. Cutting the housing at the
light-output opening thereof along a plane that extends at an angle
to the center longitudinal axis crates a light fixture with a very
small installation depth, that is a compact design. In order to
achieve the desired lighting characteristic, unneeded reflector
sections can be severed and discarded.
[0064] A reflector that is made according to this advantageous
embodiment of the invention allows the segments, which comprise
different, individually shaped reflection surfaces, to be provided
in any distribution along the interior of the reflector element.
The segments may be rotation asymmetrical, while the housing is
substantially rotation symmetrical about its center longitudinal
axis. While the outer surface of the reflector element is rotation
symmetrical prior to severing the reflector element along the cut
plane, the reflective inner surface is preferably provided with
differently rotation-asymmetrical arcuate segments.
[0065] According to a further advantageous embodiment of the
invention, the spread lens is mounted on the cut plane. As a
result, a particularly compact shape of the light fixture becomes
possible.
[0066] According to a further advantageous embodiment of the
invention, at least several of the segments are each formed by a
section of a cylinder, particularly a circular cylindrical body.
The use of cylindrical segments advantageously enables the desired
radiation characteristic of the light fixture to be achieved along
a first direction. All segments in the interior of the reflector
element are preferably formed by cylindrical bodies, particularly
circular cylindrical bodies.
[0067] The center longitudinal axis of the cylinder, referred to as
the cylinder axis, is preferably oriented substantially parallel to
the center longitudinal axis of the reflector or angled relative to
the same at an angle of less than 45.degree.. The cylinder axis is
the axis of a cylindrical segment, which is the center longitudinal
axis of the corresponding circular cylinder that provides the
cylinder surface. The angles of the cylinder axes may vary with
spacing of the cylinder from the apex region of the reflector. By
varying the inclinations of the center lines of the cylinders, the
desired light radiation characteristic can be implemented in a
particularly optimized manner.
[0068] Furthermore, tangents are formed on the outer surface of the
reflector in a connecting region of a cylindrical segment to the
reflector. Between the respective tangent and cylinder axis of the
associated segment, an angle of deviation is located. This angle of
deviation can advantageously vary with the varying distance of the
segment from the apex region. For this purpose, reference is made
to the above-mentioned German patent application DE 10 2007 035 396
by applicant, which describes in detail the advantages of segments
shaped this way, and the content of which is hereby also included
by reference in the present patent application, also for the
purpose of referring to individual characteristics.
[0069] According to a further advantageous embodiment of the
invention, the angles of the cylinder axes of the cylindrical
segments, particularly along an angle of circumference, are
advantageously selected such that the light rays impinging upon the
cylindrical segments intersect at a focal point when using a
punctiform light source. This enables, for example, the imitation
of a reflector having an elliptical cross-section, even if the
reflector element uses a housing having a shape with a parabolic
cross-section. In this way, elliptical reflectors can be imitated,
while at the same time making light fixtures with very small
installation depths.
[0070] According to a further advantageous embodiment of the
invention, the focal point is located outside the light-output
opening of the reflector element. Furthermore, the focal point is
advantageously located close to the light-output opening of the
light fixture. This enables a particularly optimized light
distribution and a particularly compact light fixture.
[0071] According to a further advantageous embodiment of the
invention, the cylinder axes of a plurality of cylinders,
particularly of a partial region of the interior of the reflector
element, with the region being explained in more detail
hereinafter, having the same distances to the apex region of the
reflector form the same angles with the center longitudinal axis of
the reflector element. This enables particularly uniform
illumination of the building surface.
[0072] According to a further advantageous embodiment of the
invention, the inner surface of the reflector element is provided
with segments around its entire circumference. This enables a
particularly optimized adjustment of the light fixture to the
desired radiation characteristics.
[0073] According to a further advantageous embodiment of the
invention, the inner surface of the reflector element is divided
into at least two partial regions. Segments of different types, for
example segments of a first type and segments of a second type, can
be provided in different partial regions. Segments of a first type
may imitate the reflection behavior of a reflector having a
parabolic cross-section, and segments of a second type may imitate
the reflection behavior of a reflector having an elliptical
cross-section. In the different partial regions, it is also
possible that segments of different sizes, elongated differently in
the axial direction, and differently arcuate or different bent
segments may be provided. It is also possible that the number of
columns and the number of rows of the segments vary in the
different partial regions. A first partial region preferably
extends over an angle of 180.degree. and a second partial region
over an angle of 180.degree.. In a different embodiment of the
invention, more than two partial regions having different angles of
circumference may be provided.
[0074] The segments may be arrayed in circular rows about the
center longitudinal axis of the reflector and along columns
extending transversely of the rows.
[0075] In one of the two partial regions, the number of rows of
segments is preferably higher, preferably twice as high, as the
number of rows of segments in the other partial region.
Furthermore, in the partial region with the higher number of rows,
the segments of two adjoining segments in the axial direction,
respectively, are preferably provided offset relative to one
another angularly such that a imbricated structure is obtained.
[0076] Furthermore, due to a severing of the produced reflector
element along a cut plane obliquely to the center longitudinal axis
of the reflector element, the number of segments in a column
preferably varies as a function of the angular dimension of the
column.
[0077] According to a further advantageous embodiment of the
invention, the first partial region and the second partial region
are separated by a boundary plane. In the first partial region
preferably segments are provided that primarily imitate a
reflection behavior of a reflector having a parabolic
cross-section, and in the second partial region segments are
provided that primarily imitate a reflection behavior of a
reflector having an elliptical cross-section.
[0078] The boundary plane and the cut plane meet in a straight
line. This straight line is oriented perpendicular to the center
longitudinal axis of the reflector element.
[0079] The largest cross-sectional area of the reflector element is
on a section through the reflector element along the center
longitudinal axis thereof, the section being made perpendicular to
the boundary plane. The largest cross-sectional area of the
reflector element is hence on a cross section of the reflector
element, comprising the segment farthest remote from the apex
region and the segment oriented 180.degree. opposite thereof at the
free edge of the reflector element.
[0080] When viewing a largest cross-sectional area of the reflector
element, a plurality of segments of a first type are provided on
the first side of the center longitudinal axis of the reflector
element and a plurality of segments of the second type are provided
on the other, opposite side of the center longitudinal axis of the
reflector element. This observation illustrates that the reflector
element comprises two essential, characteristic regions with
different features regarding the light beam and/or reflection
characteristic. The region of the reflector element that is remote
from the building surface to be illuminated comprises a plurality
of segments that imitate the reflector behavior of an elliptical
reflector, and the segments of the reflector element provided on
the side of the center longitudinal axis that is close to the
building surface to be reflected imitate the reflection behavior of
a reflector having a parabolic cross-section.
[0081] According to a further advantageous embodiment of the
invention, when viewing a cross-sectional area that is oriented
perpendicular to the largest cross-sectional area, a symmetrical
reflector element relative to the center longitudinal axis is
apparent. The observation in this embodiment of the invention is
thus made along a plane that extends parallel to the boundary
plane. When observing such cross-sectional areas, the reflector
element appears to be completely symmetrical. This embodiment is
particularly advantageous in order to achieve especially uniform
illumination of the building surface.
[0082] According to a further advantageous embodiment of the
invention, the spread lens ensures the spreading of the light in a
direction transversely to the largest cross-sectional area.
Spreading is thus performed in a direction along the boundary
plane.
[0083] The spread lens comprises a plurality of cylindrical lenses,
for example formed by a plurality of ribs extending transversely to
the boundary plane, in other words, along a direction parallel to
the largest cross-sectional area. The cylindrical lenses preferably
extend in a direction along the cut plane.
[0084] Furthermore, the light fixture is advantageously a
wallwasher.
[0085] This enables a particularly uniform illumination of the
wall.
[0086] Furthermore, the light fixture is advantageously a recessed
light fixture or as a spotlight to be installed on the ceiling.
This enables a uniform illumination even of regions on the vertical
wall close to the ceiling.
[0087] According to a further advantageous embodiment of the
invention, a partial region of the reflector for imitating a light
distribution of a parabolic reflector is oriented relative to the
light source such that the light reflected thereon primarily
illuminate a region of the light fixture remote from the light
fixture. Similarly, advantageously the regions of the reflector
imitating the light distribution of a reflector having an
elliptical cross-section are oriented such relative to the light
source that the light beam portions reflected therein primarily
illuminate a region of the building surface close to the light
fixture. In this way, even very high vertical building surfaces can
be illuminated.
[0088] The invention furthermore relates to a method for producing
a reflector element made of a starting material workpiece according
to claim 59.
[0089] Methods for producing reflector elements that are rotation
symmetrical about the center longitudinal axis thereof are
known.
[0090] It is the object of the invention to further develop a known
method for producing a reflector element such that a reflector
element can be produced that allows the development of light
fixtures in compact designs.
[0091] The invention achieves this object with the characteristics
of claim 59.
[0092] Compared to known methods for producing a reflector element,
according to the invention a section of the reflector element is
cut off along a separation plane. The separation plane extends at
an angle to a center longitudinal axis of the reflector element. At
an angle shall mean that severing occurs along an acute angle to
the center longitudinal plane, preferably along an angle ranging
between 30.degree. and 50.degree.. Furthermore, with respect to the
angle of the plane, the inclination of the separation or cut plane
preferably corresponds to the desired shielding angle of the light
fixture in the installed state to be provided by the dark light
reflector.
[0093] The invention furthermore relates to a light fixture
according to claim 60.
[0094] It is the object of the present invention to further develop
a known light fixture by the applicant, the light fixture having
been described above and known by prior public use, such that
greater variability of the illumination of building surfaces is
possible.
[0095] The invention achieves this object with the characteristics
of claim 60.
[0096] The principle of the invention is essentially to provide a
first reflector element for the light fixture, a plurality of
segments comprising surfaces that are arcuate inwardly being
provided in the interior of the element. In addition, a second
reflector element is provided that can replace the first reflector
element. The second reflector element has outer dimensions that are
identical or very similar to those of the first reflector element.
This means that the basic shape of the second reflector element
corresponds to the basic shape of the first reflector element. Also
the second reflector element is cut or truncated obliquely or at an
angle to the center longitudinal axis, or comprises an oval
opening, the edge of which is oriented along a plane that is
oriented at an angle to the center longitudinal axis of the
reflector element. Also the oval light-output opening has identical
dimensions in both reflector elements, so that the same spread lens
can be used for the first or second reflector element.
[0097] Compared to the first reflector element, however, the second
reflector element is provided with a different number or type or
configuration or curvature of segments. For example, the radii of
curvature of the segments can be oriented differently, or a
different orientation of the cylinder axes of cylindrical segments
may be provided. The type or configuration of the segments is
varied as desired in order to achieve a defined light radiation
characteristic. This light radiation characteristic that is
produced by the second reflector element, differs from the light
radiation characteristic that the first reflector element can
produce using the same light source.
[0098] While with the aid of the spread lens, for example, uniform
illumination of the wall across a large vertical height can be
produced with the first reflector element, when replacing the first
reflector element with the second reflector element, for example, a
focus area, in other words, a lighting focus area, of the building
surface to be illuminated in a certain location can be
achieved.
[0099] The second reflector element has the same dimensions as the
first reflector element, so that it can be installed and attached
in the existing light fixture housing with the same fastening means
and using the same spread lens. This enables a modular light
fixture design and the use of a second reflector element instead of
an existing first reflector element provided at the point of use.
By replacing a first reflector element with a second reflector
element, a desired, completely different light radiation
characteristic can be produced.
[0100] Further advantages of the invention are disclosed in the
dependent claims, which have not been cited, as well as the
description provided hereinafter by way of example of the
embodiment illustrated in the drawings, wherein:
[0101] FIG. 1 is a first example of the light fixture according to
the invention in a very schematic illustration, comprising a
trough-shaped housing that is provided at the bottom and
illuminates a housing wall,
[0102] FIG. 2 is a schematic cross-sectional end view of the light
fixture according to FIG. 1, approximately along section line II-II
of FIG. 1,
[0103] FIG. 3 is a schematic illustration of the light fixture
according to FIG. 2, illustrating the housing and the shape of the
light source, approximately along section line III-III of FIG.
2,
[0104] FIG. 4 is a schematic view, in a view like FIG. 1, of a
building surface to be illuminated in a first illumination
situation,
[0105] FIG. 5 is the depiction, in a view like FIG. 4, of a second,
different illumination situation,
[0106] FIG. 6 is a schematic illustration, similar to the view of
FIG. 2, of a further example of a light fixture according to the
invention a recessed light fixture,
[0107] FIG. 7 is the reflector element of the light fixture
according to FIG. 6 in a perspective view, the element being
provided internally with a plurality of segments,
[0108] FIG. 8 is a schematic view like FIG. 1, an installation
situation for illuminating a building surface, the light fixture
according to FIG. 2 being mounted on the ceiling,
[0109] FIG. 9 is a separate view of a spread lens that is used for
the light fixture according to FIG. 6, in a schematic illustration
not to scale, approximately along the on the plane line IX-IX of
FIG. 6, a dark-light reflector section of the light fixture
according to FIG. 6 having been left out for sake of clarity,
[0110] FIG. 10 is the lens plate in a schematic, partially
sectional view approximately along section line X-X of FIG. 9,
[0111] FIG. 11 is a diagram of the light-intensity distribution
obtained when using a light fixture according to FIG. 6 in an
installation situation according to FIG. 8 on a wall 15 to be
illuminated if the spread lens provided in the light fixture
according to FIG. 6 is removed,
[0112] FIG. 12 is an illustration according to FIG. 11 of the
light-intensity distribution on the wall 15 to be illuminated when
using a light fixture according to FIG. 6 with a spread lens,
[0113] FIG. 13 is a view of the interior of the reflector element
according to FIG. 7, approximately according to arrow XIII of FIG.
7,
[0114] FIG. 14 is a schematic cross-sectional view of the reflector
element according to FIG. 13, approximately along section plane
VI-VI, the illustration according to FIG. 14 showing the reflector
element immediately after manufacture, before the cutting or
severing step, whereas the reflector element according to FIG. 13
is the reflector element after completion, that is after the
severing step and after cutting off a piece 75,
[0115] FIG. 15 is an enlarged detailed view of an edge region of
the reflector element from FIG. 14 according to the circle XV of
FIG. 14,
[0116] FIG. 16 is an illustration comparable to FIG. 14 of the
reflector element in a schematic view, showing the orientations of
the cylinder axes, and
[0117] FIG. 17 is an enlarge illustration of a region of the inner
surface of the reflector element comprising segments as shown by
circle XVIII of FIG. 13.
[0118] A first embodiment of the inventive light fixture is
indicated overall in the figures with reference numeral 10. With
respect to the description of the figures below, it should be noted
that insofar as different parts or elements are indicated in the
figures, they are identified with the same reference numerals, in
part by adding lower-case letters. This also applies to different
exemplary embodiments of the invention.
[0119] According to FIG. 1, the inventive light fixture 10 is
provided with a housing 11 and a light source 12 and serving as an
in-ground light fixture. For this purpose, it is installed in the
floor 13 of a building room or an exterior space and mounted
substantially flush with the upper surface of the floor 13, as will
be apparent below from FIG. 2.
[0120] In the example according to FIGS. 1 to 3, the light fixture
is an axially elongated light fixture comprising a substantially
trough-shaped housing 11.
[0121] FIG. 1 shows how the light fixture is installed in the floor
in the installation situation according to FIG. 1 and serves to
illuminate the building wall 15. Arrows 18, 19, and 20 are intended
to illustrate that different vertical surface regions of the
building surface 15 can be illuminated. Alternatively, the light
fixture 10 however can also be ceiling-mounted, that is to say it
can be installed in or on the ceiling wall 14, and uniformly
illuminate the building surface 15. Finally, it is also possible to
mount the building light fixture 10 on the side wall 16 or 17 in
order to illuminate the building surface 15. It is likewise
conceivable that the light fixture 10 serving as an in-ground light
fixture in an installation situation according to FIG. 1 does not
illuminate the building wall 15, but the building wall 16 or the
building wall 17.
[0122] In FIG. 1, the spatial coordinate system is illustrated by
the arrows x, y, and z. The double arrow x indicates the axial
extension of the light fixture and the double arrow z a direction
transverse to the axial extension, specifically the vertical
height. The double arrow y that is only indicated in FIG. 1 with
reference to the floor surface 13, describes a further lateral
extension to the axial direction x, specifically the spatial
depth.
[0123] It is best apparent from FIG. 2 that the housing 11 is
substantially dished. The light source 12 is provided on the
interior 31 of the housing 11. It is an axially elongated light
source, for example an axially elongated HID lamp. The housing 11
comprises a wall region 21 with an elliptical cross-section. The
elliptical wall region 21 is associated with a focal point F, the
light source 12 being oriented relative to the elliptical wall
region 21 such that the center longitudinal axis M thereof (FIG. 3)
lies on the focal point axis F. The rays emitted by the light
source 12 and reflected on the elliptical reflector surface 21
therefore meet at a second focal point B that is located at a cover
glass 25 of the light fixture. The indicated light beam 29c, which
is direct light, likewise extends through the second focal point
B
[0124] The housing 11 furthermore comprises a second reflector wall
region 22 that has a parabolic cross-section. The wall region 22 is
oriented such that the focal point of the parabola coincides with
the focal point F of the elliptical wall region 21.
[0125] In an embodiment of the invention that is not illustrated,
the wall region of the reflector having a parabolic cross-section
is oriented such that the focal point of the parabolic wall region
is provided at a distance from the focal point of the elliptical
wall region 21. The light source can then be provided either on the
focal point of the elliptical wall region or on the focal point of
the parabolic wall region or between the two focal points or in the
vicinity of the two focal points.
[0126] Starting from the light source 12, direct light, indicated
by the beams 29a, 29b, and 29c, and indirect light, indicated by
the beams 30a, 30b, and 30c, reach a spread lens 23. The indirect
light, which starting from the light source 12 is reflected on the
parabolic wall region 22 before impinging upon the spread lens 23,
all reaches the lens plate along a parallel main radiation
direction H, illustrated by the light beam 30a.
[0127] The spread lens can be, for example, made of clear glass or
slightly matte-finished glass that is provided with cylindrical
lenses. In the example according to FIG. 2, the lens plate has a
substantially rectangular basic shape that corresponds
approximately to a shape K of the housing 11 according to FIG. 3.
The spread lens can be embossed glass or sheet glass.
[0128] The cross-section of the lens plate is indicated
schematically in FIG. 10 in accordance with plane X-X of FIG. 2.
The spread lens 23 can accordingly comprise an inner face 32 and an
outer face 33. On the inner face 32 of the lens plate 23, a
plurality of cylindrical lenses 34a, 34b, and 34c are provided. A
beam of rays, which according to FIG. 10 is illustrated as being
parallel, is widened under a divergence angle w as a function of
the focal length of the cylindrical lenses.
[0129] Comparable spreading of course also occurs when the light
beam occurring on the inner face 32 of the spread lens does not
impinge entirely parallel, as is the case in the example of the
light fixture according to FIGS. 1 to 3, but instead arriving from
different directions.
[0130] The cylindrical lenses 34a, 34b, 34c have a constant
cross-section along a direction transverse to the view plane of
FIG. 10. Each cylindrical lens 34a, 34b, 34c has an elongated
shape. The longitudinal extension of the cylindrical lenses is thus
oriented transversely to the axial extension x of the trough-shaped
housing 11 and transversely to the axial longitudinal extension of
the light source 12.
[0131] The cylindrical lenses may have an axial dimension that
corresponds to the axial dimension of the spread lens 23. In an
alternative embodiment of a spread lens 23, which is not shown, the
cylindrical lenses can also be formed by axially short sections of
cylindrical lenses.
[0132] While the lenses in the example according to FIG. 10 are
convex lenses on the inner face 32, alternatively also concave
lenses can be used, achieving the same lighting effect.
[0133] It is apparent from FIG. 2 that the provision of the
elliptical wall region 21 combined with the provision of the
parabolic wall region 22 on the vertical wall 15 generates a
light-intensity distribution that illuminates the building surface
15 in the desired manner. The beam of rays reflected by the
parabolic reflector surface 22 and radiating parallel is deflected
relatively far upward and in this manner can illuminate a building
surface region located relatively far up on the vertical building
wall 15. This light beam portion is illustrated by the arrow 20 in
FIG. 1. The parabolic reflector section 22 thus substantially
serves to direct indirect light up high. In this way, for example,
a particularly high building wall, that is a wall extending high in
the z-direction, can be illuminated all the way to its uppermost
regions. If a light fixture 10 according to FIG. 2 is mounted in
the ceiling, similarly a region relatively far down on a vertical
building surface can be illuminated.
[0134] In general, it can be noted that by provision of the
parabolic wall region 22 a building surface region that is far
remote from the light fixture 10 can be illuminated.
[0135] At the same time, the arrangement of the elliptical wall
region 21 enables the illumination of a building surface region
close to the light fixture 10, relative to FIG. 1 a central region
that is indicated for example by the arrow 19 in FIG. 1. Finally,
the direct light, which is indicated by the beams 29a, 29b in FIG.
2 or by the arrow 18 in FIG. 1, can illuminate lower building
surface regions, that is regions close to the light fixture.
[0136] It is noted that the observations above are illustrated in a
very simplified manner for reasons of clarity. Overall, however, it
can be stated that by using and mixing direct light and indirect
light, where the indirect light is reflected on elliptically shaped
reflector sections and on parabolic reflector sections, overall a
particularly uniform light-intensity distribution can be
achieved.
[0137] In this way, both building surface regions close to the
light fixture and also building surface regions remote from the
light fixture can be homogeneously illuminated.
[0138] To further illustrate the principle according to the
invention, reference is made to FIGS. 4 and 5 that substantially
correspond to the illustration in FIG. 1.
[0139] The hatched region indicated on the vertical building wall
15 is intended to represent a region to be illuminated by the light
fixture 10. As is apparent from FIG. 4, the entire vertical
building wall 15 is supposed to be illuminated substantially
uniformly. Such a lighting situation is desired, for example, when
paintings 35a, 35b in a museum are supposed to be illuminated.
[0140] By contrast, FIG. 5 shows an illumination situation on a
vertical wall 15, where only an upper region of the wall is to be
illuminated, for example because in the upper region of the
vertical wall goods 36a, 36b are provided, for example on a shelf
37 that are supposed to be highlighted. Both illumination
situations according to FIGS. 4 and 5 can be achieved using a light
fixture 10, the light fixture to be used in each case comprising
different reflector sections 21, 22.
[0141] FIG. 2 furthermore shows that in the light radiation
direction, for example in the main radiation direction H, a
dark-light reflector 26 is provided behind the spread lens 23. The
dark-light reflector 26 shields an observer located approximately
in the spatial angle region P at a shielding angle a. The shielding
angle a can be 40.degree., for example. The dark-light reflector 26
ensures in a known manner than an observer located in the region P
does not see any light beams reflected by the dark-light reflector
26.
[0142] Also for manufacturing reasons, in the example according to
FIG. 2, a planar intermediate element 27 connects the elliptical
wall region 21 to the parabolic wall region 22. The intermediate
element preferably performs only a small or no lighting function
and serves primarily for mechanically fastening the two cylindrical
wall regions 21 and 22 to each other, particularly to increase
their mechanical stability. The intermediate element 27 can also be
made of a highly reflective material and may, under certain
circumstances, contribute to conducting light.
[0143] Furthermore, the example according to FIG. 2 indicates a
masking element 28 provided in the light radiation direction of the
light source 12 in front of the parabolic wall region 22. The
masking element 28 masks a small section of the parabolic wall
region and can ensure that the light is directed as desired. In the
example according to FIG. 2, the indicated light beam 30a extends
through the masking element 28. This is supposed to illustrate that
the masking element 28 may also be eliminated in one embodiment of
the invention. If the masking element 28 is provided in the light
path, it is preferably opaque.
[0144] The spread lens 23 is mounted transversely to the main
radiation direction H of the light fixture 10. This means that the
main radiation direction of the light fixture, the direction
indicated at H, is substantially normal to the substantially planar
spread lens. The spread lens is angled, particularly at a shielding
angle a of 40.degree., at an angle to the vertical building surface
15 to be illuminated. The cover plate 25 of the light fixture is
provided parallel to the floor surface 13 and is made particularly
of clear glass. If the light fixture is an in-ground light fixture
in accordance with FIG. 2, the cover plate 25 is aligned flush with
the floor surface and in this way eliminates any edge that could be
a tripping hazard. The cover plate can preferably also be walked
on.
[0145] If the light fixture shown in FIG. 2 is a recessed light
fixture or as a light fixture to be installed on the ceiling, the
cover plate 25 may be completely eliminated under certain
circumstances, so that the light-output opening 38 of the light
fixture is completely open.
[0146] Based on FIGS. 6 to 17, a further example of an inventive
light fixture 40 will be described hereinafter:
[0147] FIG. 6 shows an inventive light fixture 40 that is a
recessed light fixture for installation in a ceiling 14. The light
fixture 40 is used to illuminate a vertical wall 15, so that as in
FIG. 1 the same building surface 15 is illuminated, however unlike
FIG. 1 the light fixture 40 is installed in the ceiling.
[0148] It is noted that the inventive light fixture 40 can also be
a surface-mounted ceiling light fixture or a spotlight, that is
particularly that it can be installed displaceably on a spot
carrier, for example mounted on a track.
[0149] The light fixture 40 according to FIG. 6 comprises a
reflector 41, a lamp 42, a spread lens 43 and a dark-light
reflector 46. A cover glass may also optionally be provided near
the light-output opening 38 of the light fixture 40. With
installation on the ceiling, however, the cover glass is usually
not necessary.
[0150] The reflector element 41 is shown in FIG. 7 alone in a
perspective oblique view and in FIG. 13 alone in a top view,
approximately along the arrow XIII of FIG. 7. The reflector element
comprises an inner surface 69 that is provided with a plurality of
arcuate segments. The geometric shape of these segments will be
explained below with reference to FIGS. 14 to 17.
[0151] The basic shape of the reflector element 41 is substantially
parabolic in cross-section. This parabolic basic shape is apparent
when viewing the cross-section of the reflector element 41
according to FIG. 6 from the left edge 46 according to FIG. 6
across the center apex region 44 to the right edge 45 according to
FIG. 6. The focal point associated with the parabolic housing is
indicate at F in FIG. 6. In this context, however, it is noted that
FIG. 6 shows a reflector element 41 on a completely installed light
fixture 40, where a reflector element 41 having originally a
substantially rotation-symmetrical basic shape has already been
severed or cut off.
[0152] The manufacturing method will also be described in detail
hereinafter.
[0153] A lamp 42 is provided in or close to the focal point F of
the parabolic basic shape of the reflector 41. In the embodiment
according to FIG. 6, the lamp 42 is a metal-halide lamp. Such a
metal-vapor lamp has a very small, almost punctiform shining spot,
so that in this context it is also referred to as a punctiform
light source.
[0154] The lamp 42 is fastened to a light fixture housing in a
manner that is not shown. Also a reflector element 41 can also be
fastened directly to the light fixture housing, optionally by using
fastening elements cooperating with a lamp base 70. The light
fixture housing is not shown in FIG. 6 for the sake of clarity. The
electrical feed lines as well as optional electronic control lines
for a ballast for the lamp 42 have also been eliminated from FIG. 6
for simplicity reasons.
[0155] The reflector element 41 has a basic shape that is
substantially rotation-symmetrical about the center longitudinal
axis 43 thereof. FIG. 14 shows the reflector element 41 according
to FIG. 6 alone, directly after being manufactured. It is apparent
to the observer that the reflector element 41 originally extends
from the left edge 46a according to FIG. 14 via the apex region 44
to the right edge 45 according to FIG. 14. The reflector element 41
has been cut off or severed along a plane 53 after the
manufacturing process. According to FIG. 6, the cut plane 53
extends in the example particularly at an angle 71 of approximately
70.degree. relative to the center longitudinal axis 43 of the
reflector 41.
[0156] A spread lens 23 is provided on the light fixture 40 along
the cut plane 53 according to FIG. 6. The spread lens 23
corresponds to the spread lens discussed above for the embodiment
according to FIG. 2 in terms of its function. Since as a result of
such truncating of the reflector element 41, which originally was
substantially rotation symmetrical about the center longitudinal
axis 43 in terms of basic shape, now an oval light-output opening
24 exists on the reflector element 41. As is also apparent from the
view of FIG. 9 in an exaggerated view, the spread lens 23 has an
oval shape. The inside view according to FIG. 13 also shows the
oval shape of the light-output opening 24 in a true-to-scale
illustration.
[0157] As is best seen from the inside view of the reflector
element 41 according to FIG. 13, the entire inner surface of the
reflector element is divided into two partial regions 72 and 73.
The two partial regions 72 and 73 are separated from each other
along a boundary plane 51.
[0158] The segments of the partial region 72 primarily serve to
imitate the reflection behavior of a reflector having an elliptical
cross-section. The segments provided in the partial region 73 of
the reflector 41 substantially serve to imitate the reflection
behavior of a reflector having a parabolic cross-section.
[0159] In FIGS. 14 and 16, only the segments of the first partial
region 72 are indicated and the segments of the second partial
region 73 have been left out for the sake of clarity.
[0160] As is apparent from the view of FIG. 14, a plurality of
segments extend from the apex region 44 to the right edge 45 of the
reflector element 41 according to FIG. 14, where only the segments
close to the edges 59a, 59b, 59c, 59d, 59e are referenced. The
indicated light beams illustrate that the light beams starting from
the light source in the focal point F are reflected on the segments
and come together at a second focal point B located outside the
light-output opening 24 of the reflector element 41.
[0161] The light that starts from the focal point F and does not
impinge upon segments of the second partial region 73, the segments
not being shown, can leave the reflector 41 as parallel beams.
[0162] FIG. 15 indicates that between every two segments of the
first partial region 72 adjoining each other in the axial direction
along the center longitudinal axis 43, for example between the
adjoining segments 59b and 59c, also radial undercuts 60c may be
provided. While the dotted lines in FIG. 15 indicate straight lines
extending parallel to the center longitudinal axis 43 of the
reflector element, the open spaces indicated at 60c, 60d, and 60e
illustrate that radial undercuts may be provided between two
respective adjoining segments 59b, 59c, 59d, 59e. Such radial
undercuts are described in detail in the above-mentioned
post-published German patent application DE 10 2007 035 528 by
applicant, and this application is hereby included by reference for
the purpose of avoiding repetitions to explanations provided there,
also for the purpose of including individual characteristics.
[0163] It is noted that the provision of such radial undercuts is
advantageous for the inventive light fixture, but not absolutely
essential.
[0164] FIG. 15 furthermore illustrates that the surfaces of the
segments 59b, 59c, 59d, 59e contributing to reflection are
indicated at the reference numerals 61c, 61d, 61e. These
cylindrical surfaces form the surfaces of this reflector section
that in fact provide the lighting effect. On the other hand, the
front surfaces facing the light-output opening 24, for example the
surfaces 62d and 62e, have no lighting influence whatsoever on the
reflection behavior of the reflector 41.
[0165] For simplicity reasons these front surfaces are indicated at
reference numeral 62 in FIG. 13 and are shown as lightly shaded
regions. These shaded regions extend in circles about the center
longitudinal axis 43, however they vary in their shapes.
[0166] A comparison of the two partial regions 72 and 73
illustrates that in the partial regions completely different
geometric structures are apparent, it being particularly evident
that in the first partial region 72 larger surface portions on
front surfaces are provided than in the partial region 73.
[0167] FIG. 16 illustrates a further aspect of an advantageous
embodiment of the inventive light fixture: In this figure, segments
59aa, 59ab, 59ac, 59ad, 59ae, 59af, 59ag, 59ah, 59ai, 59aj, 59ak,
59al, 59am provided between the apex region 44 and the free edge 45
are shown schematically. FIG. 16 illustrates that at each segment a
tangent is formed on an outer surface 74 of the reflector element
41. The tangents are indicated at 68ab, 68af, 68ai, and 68am in
FIG. 16. Tangent 68ab is formed to the outer surface 74 of the
reflector element 41 where segment 59ab is connected. Segment 59ab
is cylindrical. FIG. 17 illustrates, by way of example based on a
segment 59k, that each segment is formed by a cylindrical body
having a basic radius r and the height l. The arcuate cylindrical
surface 61k of this segment provides the actual reflection surface
of the respective segment. The cylinder axis for the segment 59k is
indicated at 66k in FIG. 17.
[0168] The cylinder axes of the segments 59ab, 59af, 59ai, and 59am
are indicated in FIG. 16 with 66ab, 66af, 66ai, and 66am. Between
the cylinder axes and the respective tangents, an angle of
deviation 67ab, 67af, 67ai, and 67am is provided. This angle of
deviation can vary with a spacing of the respective segment from
the apex region 44.
[0169] In this way, it is possible to generate a reflection
behavior as indicated in FIG. 14 and FIG. 6. The first partial
region 72 of the reflector element 41 thus primarily serves to
generate the reflection behavior of a reflector having an
elliptical cross-section, so that the light beams come together in
a focal point B. In FIG. 6, the light beams are indicated by way of
example with 47a, 47b, 47c, and 47d and meet in a focal point B
that is located approximately at a light-output opening 38 of the
light fixture.
[0170] The light beams 48a, 48b, 48c emitted by the light source 42
according to FIG. 6 exit the light fixture 40 in a substantially
parallel manner. If the light fixture 40 is installed in a ceiling,
as is indicated for example in FIG. 6, the light beams reflected on
the first region 72 primarily serve to illuminate a region of the
building surface 15 to be illuminated that is close to the light
fixture, while the light beams reflected on the second partial
region 73 primarily serves to illuminate a region of the building
surface 15 that is remote from the light fixture.
[0171] In this context it is noted that direct light is not shown
in FIG. 6, but instead has been left out for the sake of
clarity.
[0172] It shall also be noted that FIGS. 14 to 17 should be
understood to serve only as examples and are provided for
explaining the invention. According to the invention, also in the
respective partial region 73 preferably a plurality of segments are
provided that are formed by cylindrical bodies, as is shown for
example in FIGS. 7 and 13.
[0173] FIG. 13 illustrates that the segments are provided in
circular rows about the center longitudinal axis 43. The segments
63a, 63b, and 63c according to FIG. 13 are thus part of a common
row. Columns extend transversely thereto. The segments 64a, 64b,
and 64c according to FIG. 13 are part of a common column.
[0174] FIG. 13 furthermore illustrates that the partial region 72
comprises twice as many rows as the partial region 73. FIG. 13 also
shows that the segments of two adjoining rows of segments in the
partial region 72 are offset angularly by approximately half a
column width.
[0175] FIG. 13 furthermore illustrates that the boundary plane 51
is substantially perpendicular to the largest cross-sectional area
52. FIG. 6 accordingly shows a view of the reflector element 41
along the largest cross-sectional area, that is approximately in a
view direction of the plane VI-VI of FIG. 13.
[0176] FIG. 8 illustrates the principle of the light fixture 40
according to the invention: In the absence of a spread lens 23, it
is possible through the inventive arrangement of segments in the
interior of the reflector element 41 to achieve a light
distribution having, for example, a substantially oval shape, which
is indicated by the shape line 57 in FIG. 8, for example. In order
to achieve a wide, uniform light distribution, a shape as that
shown in dotted lines 58 in FIG. 8 can be achieved with the aid of
the spread lens 23. It should be noted that the essential aspect is
not to achieve a certain shape, but to illuminate the building
surface to be illuminated particularly uniformly across the
surface.
[0177] The diagrams according to FIGS. 11 and 12 that show the
luminous intensity distributions in lines of equal luminous
intensities, are better suited than the provision of shapes. FIG.
11 accordingly shows a shape 57 according to FIG. 8 of the
light-intensity distribution on a wall 15 produced by means of a
light fixture 40, where the spread lens 23 was eliminated. FIG. 12
shows the light-intensity distribution on the same wall with the
aid of the spread lens 23. It is apparent from FIG. 12 that the
light-intensity distribution is clearly broader and that the
uniformity with respect to the light-intensity distribution from
FIG. 6 without the spread lens is greater.
[0178] It should be noted that FIGS. 9 and 10 show a spread lens
23, where in principle a spread lens 23 can be used like that
described above in the example according to FIGS. 1 to 5. It is
essential for the invention that the spread lens is provided with
lenses that ensure spreading of the light to help produce a more
uniform illumination of the building wall. Preferably cylindrical
lenses are mounted on at least one of the two faces of the spread
lens 23. FIG. 10 illustrates such cylindrical lenses on the inner
face, it being notable that the lenses can also be provided on the
outer face or alternatively on both faces.
[0179] The axial orientation of the cylindrical lenses 34a, 34b,
and 34c is such that they are extend parallel to the plane VI-VI
from FIG. 13. In this way, the light is spread along the line
indicated at reference numeral 51 in FIG. 13.
[0180] FIG. 8 illustrates that the vertical building wall 15 to be
illuminated can be illuminated with the beams 54, 55, and 56 along
the desired vertical height, the beams being intended to show the
appropriate light. In accordance with the illustration according to
FIGS. 4 and 5, the inventive light fixture 40, however, can also be
used to illuminate any desired regions of the building surface 15
to be illuminated.
[0181] It should be noted that the inventive light fixture 40
preferably comprises a reflector element 41 that is provided on its
interior entirely with segments, preferably entirely with
cylindrical segments. The teaching according to the invention,
however, also includes such light fixtures whose reflector element
41 is provided on its interior 69 with cylindrical segments only
along an angular region about the center longitudinal axis 43, the
remaining regions of the circumferential inner surface of the
reflector element 41 being provided with differently shaped
segments or left smooth.
[0182] Finally, the inventive light fixture also comprises a
reflector element that is provided on its interior with spherically
or aspherically arcuate segments. A key element of the invention in
the subject matter of claim 20 is a combination of a spread lens
with a faceted reflector divided into segments. An individual
configuration of the reflection surface with the plurality of
segments produces a radiation characteristic along a first
direction and the use of a spread lens produces appropriate
spreading in another direction.
[0183] With respect to the manufacture of a light fixture according
to FIG. 6, it should be noted that the reflector element 41 is
preferably made of press-formed aluminum. For this purpose, a
circular aluminum disk blank can be used to produce, by pressing
against a rotating male mold, a dished reflector element that is
substantially rotation-symmetrical in its basic shape. The male
mold, which is not shown, is provided with appropriate formations
on the outer surface, where these outer formations can be embossed
or pressed into the interior of the reflector element 41. Removal
of the mold from the reflector element is possible in the axial
direction. When providing undercuts, as is indicated in FIG. 15,
preferably also a multi-part tools can be used that is described in
the abovementioned post-published patent application by the
applicant.
[0184] After removing the mold from the reflector element, the
element can be cut along the plane 53. Starting from FIG. 14,
severing by means of sawing or slicing, for example, is performed
such that a cutting tool is displaced relative to the fixed
reflector element 41 along the plane 53. The region between the
original free edge 46a and the new edge 46 after severing the
separating piece 75, that is the separating piece 75, is removed
and is scrapped.
[0185] The resultant reflector element 41 comprising the now oval
light-output opening 24 can be installed in the light fixture 40
and has a particularly compact design. In a particularly
advantageous embodiment, the center longitudinal axis 43 of the
reflector element 41 extends at an angle to the ceiling 14 in the
installed state of the light fixture 40.
[0186] FIG. 6 furthermore shows a dark-light reflector section 26
that enables shielding at a shielding angle of approximately
40.degree..
[0187] With respect to the principle of dark-light reflector
technology, reference is made to published prior art by the
applicant and the knowledge of the person skilled in the art. The
dark-light reflector section 26 makes it possible to prevent glare
for an observer located in the angular space P with the angle
.alpha. by light beams reflected on the reflector 26.
[0188] For a better understanding of the geometric design of the
reflector, it should be noted that the boundary plane 51 extends
between the partial regions 72 and 73 when viewing FIG. 6 along the
center longitudinal axis 43 of the reflector element 41. The cut
plane 53 intersects the boundary plane 51 along a straight line
indicated at reference numeral 76. This straight line extends
perpendicular to the paper plane according to FIG. 6 and hence
perpendicular to the center longitudinal axis 43 of the reflector
element.
[0189] In the two examples according to FIGS. 2 and 6, in the
installed state of the light fixture, the spread lens 23 is angled
at an acute angle relative to the wall to be illuminated,
preferably at an angle of approximately 50.degree.. The spread lens
23 can furthermore also preferably be angled at an angle ranging
between 20.degree. and 70.degree. relative to the wall to be
illuminated.
* * * * *